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NOTES ON TAXONOMY AND BIOLOGY: Meloidogyne fallax is morphologically similar to the Columbia root-knot nematode (M. chitwoodi). It differs form the Columbia root-knot nematode by a longer stylet of females and males and by the longer tail and hyaline portion of the tail of second stage juveniles (J2). Biochemical and molecular techniques to separate the two species include: isozyme patterns esterase and malate dehydrogenase, fatty acid binding protein, and species specific primers (Karssen, 1994; Peterson et al., 1997; Tastet et al., 2001). This root-knot nematode has sedentary endoparasitic habits. Second-stage juveniles (J2) in the soil penetrate host roots where they establish a specialized feeding site (giant cells) in the stele. As J2 develop, they cause small and rounded apical root swellings and become swollen females. Gravid females produce egg masses protruding from the root surface (CAB International, 2001; EPPO, 2001).
GEOGRAPHICAL DISTRIBUTION: This European species has been reported in Belgium, France, Germany and the Netherlands. Recently it has been detected in Australia (CAB International, 2001; Nobbs et al., 2001).
HOSTS: The false Columbia root-knot nematode shares with the Columbia root-knot nematode the following hosts: alfalfa (Medicago sativa), carrot (Daucus carota), potato (Solanum tuberosum), sugarbeet (Beta vulgaris), and tomato (Lycoperiscon esculentum). Other hosts which are not shared with M. chitwoodi include: hemerocallis (Hemerocallis sp.), Dicentra spectabilis, Oenothera erythrosepala, and Phacelia tenacetifolia. Other differential hosts which are infected by M. chitwoodi but not by M. fallax are bean (Phaseolus vulgaris) and corn (Zea mays). The following hosts of M. fallax but not reported for M. chitwoodi are artichoke (Cynara scolynus), lettuce (Lactuca sativa), and oyster plant (Scorzonera hispanica). More information is needed on the host status of cereals to M. fallax.
CROP LOSSES: The false root-knot nematode is a pest of potato. Nematode-infected tubers are downgraded and lose marketable value.
MEANS OF MOVEMENT AND DISPERSAL: Through root material, soil debris and by poorly sanitized bare root propagative plant material.
RATING: (M) Due to this nematodes's wide host range and distribution, it was given a moderate priority rating.
REFERENCES:
CAB International. 2001. Meloidogyne fallax
in Crop protection compendium, global module, 3rd editon. Wallingford,
UK: CAB International.
Epppo. 2001. Epppo PQR Database. Paris France.
Karssen, G. 1995. Morphological and biochemical
differentiation in
Meloidogyne chitwoodi populations in the Netherlands.
Nematologica 41:314-315.
Nobbs, J.M., Q. Liu, D. Hartley, Z. Handoo, V. M.
Williamson, S. Taylor, G. Walker, and J. Curran. 2001. First record og
Meloidogyne
fallax in Australia.Australian Plant Pathology 30:373.
Paterson D. J., and T. C. Vrain. 1996. Rapid identification
of Meloidogyne chitwoodi, M. hapla, and M. fallax
using PCR primers to amplify their ribosomal intergenic spacer. Fundamental
and Applied Nematology 19:601-605.
Tastet. C., F. Val, M. Lasage, L. Renault, L. Marche,
M. Bpssis, and D. Mignieri. 2001. Application of a putative fatty acid
binding protein to discriminate serologically the two European quarantine
root-knot nematodes,
Meloidogyne chitwoodi and M. fallax,
from other Meloidogyne species. European Journal of Plant Pathology
107:821-832.